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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2013 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/x86_64/memory.h>
#include <grub/x86_64/types.h>
#include <grub/symbol.h>
#include <grub/xen.h>
/* Macro to load an imm64 value stored by the C-part into %rax: */
#define MOV_IMM64_RAX(var) .byte 0x48, 0xb8; VARIABLE(var); .quad 0
.p2align 4 /* force 16-byte alignment */
VARIABLE(grub_relocator_xen_remap_start)
LOCAL(base):
/* Remap the remapper to it's new address. */
MOV_IMM64_RAX(grub_relocator_xen_remapper_virt)
movq %rax, %rdi /* %rdi: new virtual address of remapper */
movq %rax, %rbx /* Remember new virtual address */
MOV_IMM64_RAX(grub_relocator_xen_remapper_map)
movq %rax, %rsi /* %rsi: page table entry */
movq $UVMF_INVLPG, %rdx /* %rdx: flags (inv. single entry) */
movq $__HYPERVISOR_update_va_mapping, %rax
syscall /* Do the remap operation */
addq $(LOCAL(cont) - LOCAL(base)), %rbx
jmp *%rbx /* Continue with new virtual address */
LOCAL(cont):
/* Modify mappings of new page tables to be read-only. */
MOV_IMM64_RAX(grub_relocator_xen_mfn_list)
movq %rax, %rbx /* %rbx is the base of the p2m list */
leaq EXT_C(grub_relocator_xen_paging_areas) (%rip), %r8
1:
movq 0(%r8), %r12 /* Get start pfn of the current area */
movq GRUB_TARGET_SIZEOF_LONG(%r8), %rcx /* Get # of pg tables */
testq %rcx, %rcx /* 0 -> last area reached */
jz 3f
2:
movq %r12, %rdi
shlq $PAGE_SHIFT, %rdi /* virtual address (1:1 mapping) */
movq (%rbx, %r12, 8), %rsi /* mfn */
shlq $PAGE_SHIFT, %rsi
orq $(GRUB_PAGE_PRESENT | GRUB_PAGE_USER), %rsi /* Build pte */
movq $UVMF_INVLPG, %rdx
movq %rcx, %r9 /* %rcx clobbered by hypercall */
movq $__HYPERVISOR_update_va_mapping, %rax
syscall
movq %r9, %rcx
incq %r12 /* next pfn */
loop 2b
addq $(2 * GRUB_TARGET_SIZEOF_LONG), %r8 /* next pg table area */
jmp 1b
3:
/* Switch page tables: pin new L4 pt, load cr3, unpin old L4. */
leaq EXT_C(grub_relocator_xen_mmu_op) (%rip), %rdi
movq $3, %rsi /* 3 mmu ops */
movq $0, %rdx /* pdone (not used) */
movq $DOMID_SELF, %r10
movq $__HYPERVISOR_mmuext_op, %rax
syscall
/* Continue in virtual kernel mapping. */
MOV_IMM64_RAX(grub_relocator_xen_remap_continue)
jmp *%rax
VARIABLE(grub_relocator_xen_paging_areas)
/* array of start, size pairs, size 0 is end marker */
.quad 0, 0, 0, 0, 0, 0, 0, 0
VARIABLE(grub_relocator_xen_mmu_op)
.space 256
VARIABLE(grub_relocator_xen_remap_end)
VARIABLE(grub_relocator_xen_start)
/* Unmap old remapper area. */
MOV_IMM64_RAX(grub_relocator_xen_remapper_virt2)
movq %rax, %rdi
xorq %rax, %rax /* Invalid pte */
movq %rax, %rsi
movq $UVMF_INVLPG, %rdx
movq $__HYPERVISOR_update_va_mapping, %rax
syscall
/* Prepare registers for starting kernel. */
MOV_IMM64_RAX(grub_relocator_xen_stack)
movq %rax, %rsp
MOV_IMM64_RAX(grub_relocator_xen_start_info)
movq %rax, %rsi
cld
MOV_IMM64_RAX(grub_relocator_xen_entry_point)
/* Now start the new kernel. */
jmp *%rax
VARIABLE(grub_relocator_xen_end)
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